A number of glass, crystalline ceramic, and glass-ceramic materials are known, including some materials having oxynitride compositions. Many oxide glass systems utilize well-known glass-formers such as SiO2, Bi2O3, B2O3, P2O5, GeO2, TeO2, As2O3, and V2O5 to aid in the formation of the glass. Some of the glass compositions formed with these glass-formers can be heat-treated to form glass-ceramics. The upper use temperature of glasses and glass-ceramics formed from such glass formers is generally less than 1200° C., typically about 700-800° C. The glass-ceramics tend to be more temperature resistant than the glass from which they are formed.
In addition, many properties of known glasses and glass-ceramics are limited by the intrinsic properties of glass-formers. For example, for SiO2, B2O3, and P2O5-based glasses and glass-ceramics, the Young's modulus, hardness, and strength are relatively low. These glass and glass-ceramics generally have inferior mechanical properties as compared, for example, to Al2O3 or ZrO2.
Although some glasses based on rare earth oxide-aluminum oxide (see, e.g., U.S. Pat. No. 6,482,758 (Weber) and Japanese Document No. JP 2000-045129, published Feb. 15, 2000) are known, additional novel glasses and glass-ceramic, as well as use for both known and novel glasses and glass-ceramics, is desirable.
In another aspect, a variety of abrasive particles (e.g., diamond particles, cubic boron nitride particles, fused abrasive particles, and sintered, ceramic abrasive particles (including sol-gel-derived abrasive particles) are known in the art. In some abrading applications, the abrasive particles are used in loose form, while in others the particles are incorporated into abrasive products (e.g., coated abrasive products, bonded abrasive products, non-woven abrasive products, and abrasive brushes).
The abrasive industry continues to desire new abrasive particles and abrasive articles, as well as methods for making the same.